third way - write my own function (based on code in vs1053b-patches-flac.plg).

In any case after plugin loading decoder make software reset (I hear specific sound in earphones), mp3 decoding work well, but no luck with flac..
I think that Feather is fast enough to put data to the VS1053 chip, I don't understand what's wrong.

I've checked DREQ signal activity during MP3 and FLAC "playing".
When mp3 file played oscilloscope shown ~40 Hz signal, and no signal with FLAC.
Possible that vs1053b does not decode flac-stream (yes, flac plugin is loaded)...

Both files seem to play with my C model and with vs1053b when vs1053b-patches-flac is loaded. HDAT1 should have 'fL', i.e. 0x664c.

vs1053b-patches-flac.plg seems to include the write to AIADDR (0x300), so it should start automatically. Do not give software reset after loading the code. Use the cancel procedure to cancel play instead of software reset. If you need a software reset, you can replace it by writing 0x300 to AIADDR, or reload the patch again.

Hi,
I'm in a similar position with the VS1053b and FLAC, I'm using the Adafruit Musicmaker board.
Ogg and mp3 work fine, and I appear to be loading the flac plugin correctly but I'm getting no sound and the device appears to be freezing.

I've using a particle Xenon to drive the audio, it has a 64Mhz clock.

I've tried the jumi10.ogg file linked above, and it works regardless of whether I load the patch or not. Is this normal? Is there any other way of knowing whether the plugin has correctly loaded?

I've tried reading HDAT1 and it gives me 0x4F67 for Ogg but either freezes or returns zero for flac.